GLPI - Ticket Template "Hidden Fields" need more added fields

Go to Assistance > Tickets > Template [Above Screen]

- Click on Ticket Template and modify
- Hidden Fields - I can hide some fields, but why I can't hide "Category"?? hmm...

The list of fields available to hide is retrieved with a function that has a "withtypeandcategory" option that is set to false in the context of hidden fields.
It is not clear why it is false or why type and category are linked like this. However, it has been like this for over 11 years.
I don't know how much it would affect to allow hiding both of these fields without some extensive testing.

Thank you